Screw-adjusted lifting jack



1960 P. SHAFFER SCREW-ADJUSTED LIFTING JACK Filed Dec. 3, 1957 INVENTOR.

PAUL SHAFFER ATTORNEY United States Patent SCREW-ADJUSTED LIFTING JACK Paul Shalfer, 498 Vaughn Road, Akron 19, Ohio Filed Dec. 3, 1957, Ser. No. 700,464

4 Claims. (Cl. 254-100) This invention relates to a screw-adjusted lifting jack of the type particularly useful for supporting or levelling sagging floors in a building structure.

One object of the present invention is to provide an adjustable lifting jack or post including an improved screw-adjusted extension means thereon which makes possible a substantial saving in material and manufacturing costs without impairing the requisite load-supporting strength of the lifting jack.

Another object of the invention is to provide an improved lifting jack of the character described, including a cap having a hollow dished portion thereof seated on the end of said extension, and improved means for preventing buckling of said dished portion under the load of the building structure supported by the lifting jack.

Another object of the invention is to provide relatively inexpensive means for quickly securing said cap on the end of said extension.

Other objects of the invention will be manifest from the following brief description and the accompanying drawings.

Of the accompanying drawings:

Figure 1 is a front elevation, partly broken away, of an adjustable lifting jack assembly embodying the features of the invention.

Figure 2 is an enlarged top plan view of the post shown in Figure 1.

Figure 3 is an enlarged fragmentary cross-section, on the same scale, of the upper portion of the lifting jack, taken substantially on the line 3, 3 of Figure 2.

Figure 4 is a horizontal cross-section, on the same scale, taken substantially on the line 4, 4 of Figure 3.

Referring to the drawings generally, the numeral designates a metal post unit including a tubular member 11 telescopically receivedwithin a tubular member 12 of greater diameter, member 11 being retained in a selected longitudinally extended position with respect to member 12, as by means of a pin 13 extended through aligned apertures 14 in member 11 and supported on the outer end of member 12, in known manner.

In addition to the longitudinal adjustment of the telescopic post 10, screw adjustment means 15 is provided at the top of the member 11 for powerful, relatively more accurate longitudinal adjustment of the lifting jack. To this end, a nut 16 has a reduced portion 17 for snug reception within the outer or upper end of tubular member 11, and providing an annular shoulder portion 18 which seats against the outer edge of member 11, and a threaded shaft or extension 19 is screw-threaded through the nut, as best shown in Figure 3. The extension 19 may be made from tubular metal .stock, thereby saving considerable material as compared with the solid rod. Near the upper end of the hollow extension 19 may be aligned apertures 20 for reception of a bar or like turning tool to facilitate threaded adjustment of the threaded extension in the nut 16.

Interchangeable end caps 21, 21 may be provided at the lower end of post member 12 and the upper end of extension 19. For this purpose each cap 21 may be formed, as by known stamping methods, from a disclike ,plate to have a central concave-convex dished portion 22 terminating outwardly in a flat outer face 23 for complemental seating engagement with the upper end 24 of the extension. Cap 21 has an aperture 25 centrally of the seat portion 22, for reception of a special pin 26 therethrough into tight frictional engagement within the passage or opening 27 through extension 19, the pin 26 having an enlarged head 28 engaging the inner face .29 of dished portion 22, andhaving a flat outer face 30 which is flush with the plane of the outer face of the plate 21. Thus, when the lifting jack is in fiatwise engagement with a portion of a building structure being supported, the enlarged head 28 will prevent the dished portion of the cap from buckling under the load. Spirally arranged serrations 31 may be provided on the pin 26 to extend predominately longitudinally of the same, as shown in Figure 2, these serrations being adapted to bite into the metal of extension 19, and thereby lock the pin 26 in said tight engagement with the extension somewhat in the manner of a screw threaded connection, although the pin may be driven into the position shown in Figure 3 as by means of any suitable hammering tool. The cap 21 is utilized at the lower end of the post with the dished portion 22 self-centeringly received within the tubular member 12.

In operation or use of the improved lifting jack, as for levelling or supporting a floor of -a building, the post 10 is first telescopically adjusted to an approximate length by which the distance between the top and bottom caps 21 is less than the distance between a supporting bottom surface or floor and an overhead joist or beam of a fioor to be supported (not shown), and then the pin 13 is positioned through the transversely aligned apertures 14, after which the member 11 is moved inwardly of member 12 until the pin 13 is supported at the outer edge of member 12. After the post 10 has been initially adjusted, as described, the screw threaded extension 19 is turned with respect to the nut 18, by means of a suitable tool inserted through aperture 20 of the extension, thereby further to extend the lifting jack with powerful screw action until the overhead floor is supported in desired level condition. When the lifting jack is thus positioned and adjusted, the upper face of top plate 21 and the head 30 of pin 26 will share in supporting the building structure, so that there is no tendency for the pressure of the extension 19 applied against the dished portion 22 to buckle the same in a manner which otherwise would throw the jack out of adjustment and possibly cause serious damage to various parts of the building structure.

Modifications of the invention may be resorted 'to without departing from the spirit thereof or the scope of the appended claims.

What is claimed is:

1. An adjustable post for supporting a building structure comprising an elongated supporting member having an internally threaded portion at an end thereof, an externally threaded post extension screwed in said threaded portion for longitudinal screw adjustment with respect to said supporting member, means for turning said extension in said threaded portion, said extension having an axially inwardly extending opening in the outer end thereof, a plate having a central concave-convex dished portion providing a seat on the convex sidethereof for complementally seating against said outer end of said extension and the outer face of the plate being in a plane to fit flatwise against a surface of the building structure to be supported, said plate having an aperture in said dished portion centrally of said seat thereof and adapted to be aligned with the said opening in the outer end of said extension, a pin receivable through said aperture for securement in said opening of the extension and having an enlarged head engaging the concave side of said dished portion to retain the plate seated on the extension, the outer end portion of said head being substantially flush with said outer 'face of .said plate and thereby adapted to engage said surface of the building whereby the dished portion of the plate is solidly supported against buckling of said dished portion thereof by .said head under compressive load on said member when supporting the building structure.

2. An adjustable post as set forth in claim 1, said .pin :having spirally arranged serrations thereon adapted to bite into tight gripping engagement with the material of said extension within said outer end opening thereof.

3. An adjustable post as set forth in claim 2, said outer end portion of said head being flat.

4. An adjustable post as set forth in claim, 3, said extension being of tubular metal and the passage therethrough defining said outer end opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,482,151 Rosenberg Jan. 29, 1924 2,504,291 Alderfer Apr. 18, 1950 2,826,846 Warren 7. Mar. 18, 1958 

